Computational Model for the Neutronic Simulation of Pebble Bed Reactor’s Core Using MCNPX

Table 1

Characteristics of the HTR-10 fuel element.

Parameter	Units	Value
Pebble diameter	cm	6.00
Fuel zone diameter	cm	5.00
Matrix and graphite shell density	g/cm^3	1.73
Uranium mass per pebble	g	5.00
Uranium enrichment (by weight)	%	17.00
Natural boron impurity equivalent content on uranium	ppm	4.00
Natural boron impurity equivalent content on graphite	ppm	1.30
Core packing fraction	—	0.61
Fuel core
Kernel radius	m	0.25
UO2 density	g/cm^3	10.40
Layers
TRISO layers		PyC/PyC/SiC/PyC
TRISO layers thickness	mm	0.09/0.04/0.035/0.04
TRISO layers density	g/cm^3	1.1/1.9/3.18/1.9
Dummy balls
Pebble diameter	cm	6
Graphite density	g/cm^3	1.73
Natural boron impurity equivalent content on graphite	ppm	1.30